Focus On Auxiliary Marine Equipment: Centrifugal Oil Purifiers
Centrifuges are one of the most important auxiliary equipment onboard. These centrifuges have two different operating functions aboard ships:
Clarifiers– separate solids from a liquid mixture
Purifiers– separate multiple liquids of different densities
The purifiers function by using centrifugal force at speeds specific to the application. This purification process can be optimized by adjusting certain parameters at the start of the process.
Parameters affecting the purification process
1. Inlet oil temperature
Before the feed oil enters the purifier, it is passed through a heater to increase the oil temperature. Heating reduces the viscosity of the oil, thereby improving the purification process.
2. Oil density
Apart from reducing viscosity, heating also helps lower density. This allows for a better separation, as any sediment present will be heavier in terms of density.
3. Speed of the rotating bowl
The purifier must be set at a particular rpm, according to the type of oil and amount of contaminating substances present within.
Note that centrifuges take time to start and reach the required RPM. Purification begins only when that particular speed is achieved. Lower RPM does not generate enough centrifugal force required for proper separation.
4. Back pressure
Back pressure is adjusted once the purifier starts. This pressure varies with the specifications of your use; temperature, viscosity and the density of your oil feed will determine the back pressure.
This will help you make sure that the oil paring disc is thoroughly immersed in clean oil, pumping to the clean oil tank.
5. Throughput of feed
Throughput is the volume of oil pumped in the purifier, every hour. Minimum throughput will ensure higher quality purification. It is important to not overload the equipment; otherwise, the purification process will be compromised.
Keep in mind that the exact specifications of the parameters will vary according to your feed and equipment. In addition to optimizing the process by adjusting physical parameters, performing timely inspections before and during the process also helps ensure proper separation.
Pre-checks required before starting the centrifuge
• If the purifier was overhauled and is being started for the first time after that, make sure all the fittings are accurate.
• The bowl frame hood should be properly locked with hinges.
• Also check the oil level inside the gear case. Make sure that it is half in the slight glass.
• Additionally, the slight glass should be vertically positioned. Fitting it in a horizontal position is a common error.
• Check the rotation direction of the purifier by simply starting and stopping the motor.
• Inspect the brake too. It must be in a released position.
• Adjust the specifications, including back pressure, throughput and temperature of the feed, if and when needed.
• Monitor gear case oil level, general leakages, vibration and motor amps.
• De-sludge the equipment every two hours for heavy oil purification and every four hours for lubrication oil purification.
Make sure you have marine spare parts stocked onboard, if any of the centrifuge or other parts fail.
Contact Changrun Trade, a reputed marine spares supplier. They have a range of equipment and fittings, including parts for purifiers and heat exchangers.